A new study from researchers at the Universities of Bath and Bristol suggests that doctors should rethink which drugs they prescribe to help smokers with mental health conditions kick the habit.

Their results highlight that the most effective drug at helping individuals to stop smoking is less likely to be prescribed to people with mental health conditions.

People with mental health conditions, such as anxiety or depression, are twice as likely to smoke compared to the general population. They tend to smoke more cigarettes per day, be more heavily addicted, and more likely to relapse when they try to quit. And whereas smoking rates in the UK have declined over recent decades, smoking rates have changed relatively little for people with mental health conditions.

Most smokers wishing to quit are prescribed one of two common smoking cessation drugs: nicotine replacement therapy (NRT) or varenicline. Recent randomised trials and observational studies have found that patients prescribed varenicline are more likely to stop smoking compared to those prescribed NRT.

But there have been concerns around the psychological safety of varenicline, with doctors reluctant to prescribe the drug to smokers with mental health conditions. In fact, the best evidence shows that varenicline is not associated with worse mental health outcomes.

The new study, published Wednesday 10 July in the journal Nicotine & Tobacco Research, compares rates by which patients prescribed NRT and varenicline succeed in giving up, and what effects the drugs have on individual’s mental health.

Drawing on data from over 200,000 smokers, it compares outcomes for patients with and without mental health conditions prescribed both types of drug. The results highlight that:

Compared to smokers without mental health conditions, smokers with these conditions were 31% less likely to be prescribed varenicline than NRT.

Smokers with mental health conditions who were prescribed varenicline were 19% more likely to have successfully quit at two years follow-up, than smokers who were prescribed NRT.

Varenicline is more effective than NRT in helping patients stop smoking and there was little ‘evidence that varenicline was adversely associated with poorer mental health outcomes’. In general, varenicline was associated with better mental health outcomes.

Lead researcher, Dr. Gemma Taylor from the University of Bath’s Addiction & Mental Health Group with the Department of Psychology explains: “Smoking is still the world’s leading cause of preventable illness and death. One in every two smokers will die because of their addiction unless they quit. Yet, whilst smoking rates have declined over recent decades for the general population, prevalence has not shifted to the same extent in people with mental health conditions who disproportionately suffer from smoking related mortality and morbidity and lower life expectancy.

“This study is about addressing this public health challenge to see whether assumptions about prescriptions could be challenged to give patients wishing to quit a better chance of success. Our results, in combination with results from clinical trials, suggest that doctors should rethink prescription practice in view of the benefits varenicline could bring to help those with mental health conditions stop smoking. Stopping smoking has clear physical health benefits, and there is growing evidence that stopping smoking is associated with better mental health too, benefits that could be as large as taking anti-depressants.”

The research team conducted the study using electronic medical records from 654 general practices in England from 2006-15 via the Clinical Practice Research Database.

Comparing patients’ success in quitting smoking using either NRT or varenicline, they focused on rates by which patients with mental health conditions gave up at three, six and nine month windows, as well at one, two and four years after first prescription.

The team also observed that across all patients, NRT and varenicline prescribing declined overtime. This could be because NHS Stop Smoking Services are being decommissioned from primary care.

Professor Ann McNeill, Professor of Tobacco Addiction, King’s College London and co-Chair of the Mental Health and Smoking Partnership said: “People with mental health conditions are more likely to smoke and smoke heavily than those without, and this contributes to them dying much earlier. Doctors should therefore be pulling out all the stops to help these smokers to quit, but this research involving nearly 200,000 smokers, shows that this is not happening.